mjackson

const npmApiUrl = "https://api.npmjs.org/downloads/point";

async function fetchDownloadCounts(packageName, year) {
  let range = `${year}-01-01:${year}-12-31`;
  let response = await fetch(`${npmApiUrl}/${range}/${packageName}`);
  return (await response.json()).downloads;
}

async function getDownloads(startYear, endYear = startYear) {
  if (endYear < startYear) {

mjackson

Composing <Route> in React Router v6

Composition of <Route> elements in React Router is changing in v6 from how it worked in v4/5 and in Reach Router. React Router v6 is the successor of both React Router v5 and Reach Router.

This document explains our rationale for making the change as well as a pattern you will want to avoid in v6 and a note on how you can start preparing your v5 app for v6 today.

Background

In React Router v5, we had an example of how you could create a element](https://github.com/remix-run/react-router/blob/320be7afe44249d5c025659bc00c3276a19f0af9/packages/react-router-dom/examples/Auth.js#L50-L52) to restrict access to certain routes on the page. This element was a simple [wrapper around an actual element that made a simple decision: is the user authenticated or not? If so, ren

mjackson

Redirects in React Router v6

An important part of "routing" is handling redirects. Redirects usually happen when you want to preserve an old link and send all the traffic bound for that destination to some new URL so you don't end up with broken links.

The way we recommend handling redirects has changed in React Router v6. This document explains why.

Background

In React Router v4/5 (they have the same API, you can read about why we had to bump the major version here) we had a <Redirect> component that you could use to tell the router when to automatically redirect to another URL. You might have used it like this:

mjackson

import React from "react";

export type ColorScheme = "light" | "dark";

export default function useColorSchemePreference(
  defaultColorScheme: ColorScheme = "light"
) {
  let darkQuery = "(prefers-color-scheme: dark)";
  let [colorScheme, setColorScheme] = React.useState<ColorScheme>(
    typeof window === "object" && window.matchMedia

mjackson

import React from 'react';

let DataContext = React.createContext();

// A higher-order component for pairing preload function + component ...
function withData(preloadData, Component, autoPreloadOnRender = true) {
  let needsPreload = !!autoPreloadOnRender;

  let promise;
  let value;

mjackson

let feed = {
  type: 'rss',
  props: {
    'xmlns:blogChannel': 'https://...',
    version: '2.0',
    children: [
      {
        type: 'channel',
        props: {
          title: 'Remix Blog',

mjackson

function useControl(defaultValue, value, onChange) {
  let [localValue, setLocalValue] = React.useState(defaultValue)
  let isControlled = value != null // the key

  let activeValue = isControlled ? value : localValue
  let setActiveValue = nextValue => {
    if (isControlled) {
      if (onChange) {
        onChange(nextValue)
      } else {

mjackson

expect.extend({
  toContainElement(instance, targetElement) {
    let matchingElements = instance.findAllByProps(targetElement.props);

    if (matchingElements.length === 0) {
      return {
        message() {
          let props = JSON.stringify(targetElement.props);
          return `expected to find element with props ${props}`;
        },

mjackson

import React from 'react';
import { lazy } from 'react-suspense-resource';

let Courses = lazy(() => import('./Courses.js'));
let CoursesIndex = lazy(() => import('./CoursesIndex.js'));

let routes = [
  {
    path: "courses",
    element: <Courses />,

mjackson

let routes = (
  <RankedSwitch>
    {/*
    <RankedSwitch> picks the best child <Route> that matches
    the path. Like <Switch>, it does not match deeply, so you
    need to use /* on the path if you want to do that. Like
    @reach/router's <Router>, it ranks the paths so you don't
    have to think about ordering.

    Con: You have to use /* to do deep matching